Abstract This application requests renewal of the current grant supporting the five clinical centers that comprise the Teen-LABS (TL) consortium. This multicenter, prospective, observational study of the risks and benefits bariatric surgery successfully recruited 242 consecutive adolescents undergoing bariatric surgery at participating clinical centers and has retained these subjects for long-term follow up. By the end of the current funding period (August 2016), most will have completed 5 years of follow-up. A renewal of funding will provide an opportunity to examine long- term outcomes of Roux en Y gastric bypass and sleeve gastrectomy, the most commonly used operations today. Collection of additional longitudinal measures from years 6 to10 will importantly document durability of weight loss and comorbidity resolution, quality of life, micronutrient status, and will identify long-term adverse events. Continued collection of biospecimens will continue to drive new discovery by investigators utilizing the ancillary studies mechanism. Addition of new measures to study bone health, cognitive function, and behavioral patterns will further enhance the value of an extension of the study.